Habitat: pelagic, at least to 360 m depth. Behaviour: may swim or rest in vertical position. Food: said to eat crustaceans, other in vertebrates and also algae when inshore. Reproduction: eggs very numerous and small (300 million in a female 1.50 m long). Three developmental stages:(I) tetraodontiform—body rather elongate, no spines, caudal fin present; (2) ostracioniform—body shortened, with some large spines on body plates; (3) molacanthiform (Molacanthus)—body short and high, skin rough with minute spines.

Distribution: Mediterranean, off western Europe to Scandinavia and occasionally western Baltic. Cosmopolitan.

DeKay, J. E. 1842. Zoology of New York, or the New York fauna. Comprising detailed descriptions of all the animals hitherto observed within the state borders. Class V. Fishes. Natural History of New York Geological Survey, Albany, 1 (3-4), Fishes: 415 pp., 79 pl.